Field
Embodiments of the present disclosure generally relate to semiconductor fabrication processes. More specifically, embodiments described herein relate to self-limiting and saturating chemical vapor deposition (CVD) and atomic layer deposition (ALD) methods.
Description of the Related Art
Atomic layer deposition (ALD) is a thin film deposition method in which a film is grown on a substrate by exposing its surface to alternate gaseous species (typically referred to as precursors). In contrast to chemical vapor deposition (CVD), the precursors are not present simultaneously in the reactor, but are introduced into the reaction chamber as a series of sequential, non-overlapping pulses. ALD processes are capable of producing very thin, conformal films with control of the thickness and composition of the films possible at the atomic level. As a result of the highly specific nature of ALD processes, surface characteristics of the substrate or layers formed thereon are factors which determine the characteristics of ALD films grown thereon.
CVD processes are generally considered to be non-self-limiting and utilize plasmas or catalysts to deposit films. These processes often lead to undesirable substrate oxidation, which reduces the reactivity and suitability of the as deposited film for subsequent processing. Thus, it is often difficult to form ALD films on substrates which have CVD deposited materials disposed thereon.
Thus what is needed in the art are improved CVD and ALD processes.